Just roughing up the surface with fine grit sandpaper is enough to get the paint to stick to polyurethane. With a little elbow grease, you'll be ready to paint in no time! Sanding is especially important if you plan to stain the wood a different color instead of painting it.
Sanding The Wood Surface
Sanding is one of those things people either love or hate, but whatever the case, many experts will agree it's an extremely important step if you're painting over polyurethane and you want your paint to stick properly. For smooth surfaces, you'll want to go coarse with 60- or 80-grit sandpaper.
Any type of paint is suitable for use on a polyurethane treated surface as long as the surface is pretreated, beforehand. No type of paint will stick to ill-prepared polyurethane surfaces. Improper preparation will ultimately lead to paint failure in the way of chipping and peeling.
You can, but you'll need to use a good primer first. Polyurethane creates a slick, plastic-like finish that most paints won't adhere to. A bonding primer will stick to the polyurethane and create a surface that's just textured enough to paint over easily. Think of primer as a glue.
To obtain the best possible results, apply a layer of oil-based primer to provide a better surface for the paint to adhere to and prevent any form of stains or wood from showing through the paint. Ideally, you should let it dry overnight before deciding if another coat is necessary.
Just roughing up the surface with fine grit sandpaper is enough to get the paint to stick to polyurethane. With a little elbow grease, you'll be ready to paint in no time! Sanding is especially important if you plan to stain the wood a different color instead of painting it.
Surfaces with varnish, polyurethanes, or other sealants or finishes require sanding before any paint can be properly applied. If not, the newly-painted surface will bubble, peel, crack or generally not stick.
You can remove both oil- and water-based polyurethanes from wood surfaces using paint stripper, denatured alcohol and lacquer thinner, or baking soda and vinegar.
The degloss and prime combo! Deglosser is a wonderful way to substitute the sanding process. It is a much less strenuous and much faster alternative to sanding furniture to remove varnish or lacquer. Combine this step with priming and you have a beautifully prepared surface for paint to adhere to.
Overall, spray polyurethane is an excellent option for those who want a flawless, professional-looking finish without any brush marks or streaks. It's quick to dry and is perfect for large-scale projects.
An oil-based primer is the only type of primer that is compatible with your polyurethane finish.
Even freshly finished cabinet doors won't look good if the cabinets are too worn or damaged. If it's just the finish or the hardware that's worn, but the wood itself is still solid, you should get good results from painting kitchen cabinets.
A polyurethane varnish finish can cut down on the wear and tear of kitchen cabinets, help keep them looking new and extend the life of the cabinets. Polyurethane works best on unfinished wood but can also be painted directly onto painted surfaces.
When you use vinegar on polyurethane finished wood, the acid in the vinegar breaks down the finish and starts to pit the finish. These pits trap sand and along with the acid will eventually strip the polyurethane.
Use a polyurethane stripper or paint stripper to help break down the polyurethane coating on your wood floors. Follow the instructions on the bottle for proper application. Before removing polyurethane, allow the paint stripper to soak into the polyurethane for several minutes so it can work its magic.
Digesil 2000 Gel is another highly efficient product that dissolves polyurethane. It poses a low hazard when used directly and is also extremely environmentally friendly.
If you don't sand between layers of polyurethane, the surface may become streaky or discolored. This formula prevents chemical solvents from bonding to it. Once the first layer of paint is dry, you can apply a second coat to make sure everything remains. Each coat of oil-based polyurethane finishes is applied on top.
Klean-Strip QWN285 Easy Liquid Sander Deglosser
With an easy-to-use, less toxic formula that's designed to cut through grime, this liquid sander deglosser from Klean-Strip can remove paint, lacquer, polyurethane, enamel, and varnish.
And yes, you can use latex over varnish, although that might not be your best choice. But, chances are, unless the chest was handmade by someone, it doesn't even have a varnish finish anyway. Most furniture factories have been using lacquers for decades. You can also paint successfully over lacquer.
Sand the dried surface. Let the first coat dry overnight, and sand it with a 280-grit or finer sandpaper. Apply successive coats of polyurethane, sanding between each application as it dries. After the final coat, sand with 600-grit sandpaper for a sleek, smooth surface.
With the fine-grit sandpaper, softly sand down the brush markings while applying even pressure to the area. To remove any traces of dirt and grit from the sanding, wipe it off with a soft cloth. These particles may become trapped beneath the finish.